builtin/help.c

   1 /*
   2  * Builtin help command
   3  */
   4 #include "cache.h"
   5 #include "config.h"
   6 #include "builtin.h"
   7 #include "exec-cmd.h"
   8 #include "parse-options.h"
   9 #include "run-command.h"
  10 #include "config-list.h"
  11 #include "help.h"
  12 #include "alias.h"
  13
  14 #ifndef DEFAULT_HELP_FORMAT
  15 #define DEFAULT_HELP_FORMAT "man"
  16 #endif
  17
  18 static struct man_viewer_list {
  19         struct man_viewer_list *next;
  20         char name[FLEX_ARRAY];
  21 } *man_viewer_list;
  22
  23 static struct man_viewer_info_list {
  24         struct man_viewer_info_list *next;
  25         const char *info;
  26         char name[FLEX_ARRAY];
  27 } *man_viewer_info_list;
  28
  29 enum help_format {
  30         HELP_FORMAT_NONE,
  31         HELP_FORMAT_MAN,
  32         HELP_FORMAT_INFO,
  33         HELP_FORMAT_WEB
  34 };
  35
  36 enum show_config_type {
  37         SHOW_CONFIG_HUMAN,
  38         SHOW_CONFIG_VARS,
  39         SHOW_CONFIG_SECTIONS,
  40 };
  41
  42 static enum help_action {
  43         HELP_ACTION_ALL = 1,
  44         HELP_ACTION_GUIDES,
  45         HELP_ACTION_CONFIG,
  46         HELP_ACTION_CONFIG_FOR_COMPLETION,
  47         HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION,
  48 } cmd_mode;
  49
  50 static const char *html_path;
  51 static int verbose = 1;
  52 static enum help_format help_format = HELP_FORMAT_NONE;
  53 static int exclude_guides;
  54 static struct option builtin_help_options[] = {
  55         OPT_CMDMODE('a', "all", &cmd_mode, N_("print all available commands"),
  56                     HELP_ACTION_ALL),
  57         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
  58         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  59         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  60                         HELP_FORMAT_WEB),
  61         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  62                         HELP_FORMAT_INFO),
  63         OPT__VERBOSE(&verbose, N_("print command description")),
  64
  65         OPT_CMDMODE('g', "guides", &cmd_mode, N_("print list of useful guides"),
  66                     HELP_ACTION_GUIDES),
  67         OPT_CMDMODE('c', "config", &cmd_mode, N_("print all configuration variable names"),
  68                     HELP_ACTION_CONFIG),
  69         OPT_CMDMODE_F(0, "config-for-completion", &cmd_mode, "",
  70                     HELP_ACTION_CONFIG_FOR_COMPLETION, PARSE_OPT_HIDDEN),
  71         OPT_CMDMODE_F(0, "config-sections-for-completion", &cmd_mode, "",
  72                     HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION, PARSE_OPT_HIDDEN),
  73
  74         OPT_END(),
  75 };
  76
  77 static const char * const builtin_help_usage[] = {
  78         N_("git help [-a|--all] [--[no-]verbose]]\n"
  79            "         [[-i|--info] [-m|--man] [-w|--web]] [<command>]"),
  80         N_("git help [-g|--guides]"),
  81         N_("git help [-c|--config]"),
  82         NULL
  83 };
  84
  85 struct slot_expansion {
  86         const char *prefix;
  87         const char *placeholder;
  88         void (*fn)(struct string_list *list, const char *prefix);
  89         int found;
  90 };
  91
  92 static void list_config_help(enum show_config_type type)
  93 {
  94         struct slot_expansion slot_expansions[] = {
  95                 { "advice", "*", list_config_advices },
  96                 { "color.branch", "<slot>", list_config_color_branch_slots },
  97                 { "color.decorate", "<slot>", list_config_color_decorate_slots },
  98                 { "color.diff", "<slot>", list_config_color_diff_slots },
  99                 { "color.grep", "<slot>", list_config_color_grep_slots },
 100                 { "color.interactive", "<slot>", list_config_color_interactive_slots },
 101                 { "color.remote", "<slot>", list_config_color_sideband_slots },
 102                 { "color.status", "<slot>", list_config_color_status_slots },
 103                 { "fsck", "<msg-id>", list_config_fsck_msg_ids },
 104                 { "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
 105                 { NULL, NULL, NULL }
 106         };
 107         const char **p;
 108         struct slot_expansion *e;
 109         struct string_list keys = STRING_LIST_INIT_DUP;
 110         struct string_list keys_uniq = STRING_LIST_INIT_DUP;
 111         struct string_list_item *item;
 112         int i;
 113
 114         for (p = config_name_list; *p; p++) {
 115                 const char *var = *p;
 116                 struct strbuf sb = STRBUF_INIT;
 117
 118                 for (e = slot_expansions; e->prefix; e++) {
 119
 120                         strbuf_reset(&sb);
 121                         strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
 122                         if (!strcasecmp(var, sb.buf)) {
 123                                 e->fn(&keys, e->prefix);
 124                                 e->found++;
 125                                 break;
 126                         }
 127                 }
 128                 strbuf_release(&sb);
 129                 if (!e->prefix)
 130                         string_list_append(&keys, var);
 131         }
 132
 133         for (e = slot_expansions; e->prefix; e++)
 134                 if (!e->found)
 135                         BUG("slot_expansion %s.%s is not used",
 136                             e->prefix, e->placeholder);
 137
 138         string_list_sort(&keys);
 139         for (i = 0; i < keys.nr; i++) {
 140                 const char *var = keys.items[i].string;
 141                 const char *wildcard, *tag, *cut;
 142                 const char *dot = NULL;
 143                 struct strbuf sb = STRBUF_INIT;
 144
 145                 switch (type) {
 146                 case SHOW_CONFIG_HUMAN:
 147                         puts(var);
 148                         continue;
 149                 case SHOW_CONFIG_SECTIONS:
 150                         dot = strchr(var, '.');
 151                         break;
 152                 case SHOW_CONFIG_VARS:
 153                         break;
 154                 }
 155                 wildcard = strchr(var, '*');
 156                 tag = strchr(var, '<');
 157
 158                 if (!dot && !wildcard && !tag) {
 159                         string_list_append(&keys_uniq, var);
 160                         continue;
 161                 }
 162
 163                 if (dot)
 164                         cut = dot;
 165                 else if (wildcard && !tag)
 166                         cut = wildcard;
 167                 else if (!wildcard && tag)
 168                         cut = tag;
 169                 else
 170                         cut = wildcard < tag ? wildcard : tag;
 171
 172                 strbuf_add(&sb, var, cut - var);
 173                 string_list_append(&keys_uniq, sb.buf);
 174                 strbuf_release(&sb);
 175
 176         }
 177         string_list_clear(&keys, 0);
 178         string_list_remove_duplicates(&keys_uniq, 0);
 179         for_each_string_list_item(item, &keys_uniq)
 180                 puts(item->string);
 181         string_list_clear(&keys_uniq, 0);
 182 }
 183
 184 static enum help_format parse_help_format(const char *format)
 185 {
 186         if (!strcmp(format, "man"))
 187                 return HELP_FORMAT_MAN;
 188         if (!strcmp(format, "info"))
 189                 return HELP_FORMAT_INFO;
 190         if (!strcmp(format, "web") || !strcmp(format, "html"))
 191                 return HELP_FORMAT_WEB;
 192         /*
 193          * Please update _git_config() in git-completion.bash when you
 194          * add new help formats.
 195          */
 196         die(_("unrecognized help format '%s'"), format);
 197 }
 198
 199 static const char *get_man_viewer_info(const char *name)
 200 {
 201         struct man_viewer_info_list *viewer;
 202
 203         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
 204         {
 205                 if (!strcasecmp(name, viewer->name))
 206                         return viewer->info;
 207         }
 208         return NULL;
 209 }
 210
 211 static int check_emacsclient_version(void)
 212 {
 213         struct strbuf buffer = STRBUF_INIT;
 214         struct child_process ec_process = CHILD_PROCESS_INIT;
 215         const char *argv_ec[] = { "emacsclient", "--version", NULL };
 216         int version;
 217
 218         /* emacsclient prints its version number on stderr */
 219         ec_process.argv = argv_ec;
 220         ec_process.err = -1;
 221         ec_process.stdout_to_stderr = 1;
 222         if (start_command(&ec_process))
 223                 return error(_("Failed to start emacsclient."));
 224
 225         strbuf_read(&buffer, ec_process.err, 20);
 226         close(ec_process.err);
 227
 228         /*
 229          * Don't bother checking return value, because "emacsclient --version"
 230          * seems to always exits with code 1.
 231          */
 232         finish_command(&ec_process);
 233
 234         if (!starts_with(buffer.buf, "emacsclient")) {
 235                 strbuf_release(&buffer);
 236                 return error(_("Failed to parse emacsclient version."));
 237         }
 238
 239         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 240         version = atoi(buffer.buf);
 241
 242         if (version < 22) {
 243                 strbuf_release(&buffer);
 244                 return error(_("emacsclient version '%d' too old (< 22)."),
 245                         version);
 246         }
 247
 248         strbuf_release(&buffer);
 249         return 0;
 250 }
 251
 252 static void exec_woman_emacs(const char *path, const char *page)
 253 {
 254         if (!check_emacsclient_version()) {
 255                 /* This works only with emacsclient version >= 22. */
 256                 struct strbuf man_page = STRBUF_INIT;
 257
 258                 if (!path)
 259                         path = "emacsclient";
 260                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 261                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 262                 warning_errno(_("failed to exec '%s'"), path);
 263                 strbuf_release(&man_page);
 264         }
 265 }
 266
 267 static void exec_man_konqueror(const char *path, const char *page)
 268 {
 269         const char *display = getenv("DISPLAY");
 270         if (display && *display) {
 271                 struct strbuf man_page = STRBUF_INIT;
 272                 const char *filename = "kfmclient";
 273
 274                 /* It's simpler to launch konqueror using kfmclient. */
 275                 if (path) {
 276                         size_t len;
 277                         if (strip_suffix(path, "/konqueror", &len))
 278                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 279                         filename = basename((char *)path);
 280                 } else
 281                         path = "kfmclient";
 282                 strbuf_addf(&man_page, "man:%s(1)", page);
 283                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 284                 warning_errno(_("failed to exec '%s'"), path);
 285                 strbuf_release(&man_page);
 286         }
 287 }
 288
 289 static void exec_man_man(const char *path, const char *page)
 290 {
 291         if (!path)
 292                 path = "man";
 293         execlp(path, "man", page, (char *)NULL);
 294         warning_errno(_("failed to exec '%s'"), path);
 295 }
 296
 297 static void exec_man_cmd(const char *cmd, const char *page)
 298 {
 299         struct strbuf shell_cmd = STRBUF_INIT;
 300         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 301         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 302         warning(_("failed to exec '%s'"), cmd);
 303         strbuf_release(&shell_cmd);
 304 }
 305
 306 static void add_man_viewer(const char *name)
 307 {
 308         struct man_viewer_list **p = &man_viewer_list;
 309
 310         while (*p)
 311                 p = &((*p)->next);
 312         FLEX_ALLOC_STR(*p, name, name);
 313 }
 314
 315 static int supported_man_viewer(const char *name, size_t len)
 316 {
 317         return (!strncasecmp("man", name, len) ||
 318                 !strncasecmp("woman", name, len) ||
 319                 !strncasecmp("konqueror", name, len));
 320 }
 321
 322 static void do_add_man_viewer_info(const char *name,
 323                                    size_t len,
 324                                    const char *value)
 325 {
 326         struct man_viewer_info_list *new_man_viewer;
 327         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
 328         new_man_viewer->info = xstrdup(value);
 329         new_man_viewer->next = man_viewer_info_list;
 330         man_viewer_info_list = new_man_viewer;
 331 }
 332
 333 static int add_man_viewer_path(const char *name,
 334                                size_t len,
 335                                const char *value)
 336 {
 337         if (supported_man_viewer(name, len))
 338                 do_add_man_viewer_info(name, len, value);
 339         else
 340                 warning(_("'%s': path for unsupported man viewer.\n"
 341                           "Please consider using 'man.<tool>.cmd' instead."),
 342                         name);
 343
 344         return 0;
 345 }
 346
 347 static int add_man_viewer_cmd(const char *name,
 348                               size_t len,
 349                               const char *value)
 350 {
 351         if (supported_man_viewer(name, len))
 352                 warning(_("'%s': cmd for supported man viewer.\n"
 353                           "Please consider using 'man.<tool>.path' instead."),
 354                         name);
 355         else
 356                 do_add_man_viewer_info(name, len, value);
 357
 358         return 0;
 359 }
 360
 361 static int add_man_viewer_info(const char *var, const char *value)
 362 {
 363         const char *name, *subkey;
 364         size_t namelen;
 365
 366         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 367                 return 0;
 368
 369         if (!strcmp(subkey, "path")) {
 370                 if (!value)
 371                         return config_error_nonbool(var);
 372                 return add_man_viewer_path(name, namelen, value);
 373         }
 374         if (!strcmp(subkey, "cmd")) {
 375                 if (!value)
 376                         return config_error_nonbool(var);
 377                 return add_man_viewer_cmd(name, namelen, value);
 378         }
 379
 380         return 0;
 381 }
 382
 383 static int git_help_config(const char *var, const char *value, void *cb)
 384 {
 385         if (!strcmp(var, "help.format")) {
 386                 if (!value)
 387                         return config_error_nonbool(var);
 388                 help_format = parse_help_format(value);
 389                 return 0;
 390         }
 391         if (!strcmp(var, "help.htmlpath")) {
 392                 if (!value)
 393                         return config_error_nonbool(var);
 394                 html_path = xstrdup(value);
 395                 return 0;
 396         }
 397         if (!strcmp(var, "man.viewer")) {
 398                 if (!value)
 399                         return config_error_nonbool(var);
 400                 add_man_viewer(value);
 401                 return 0;
 402         }
 403         if (starts_with(var, "man."))
 404                 return add_man_viewer_info(var, value);
 405
 406         return git_default_config(var, value, cb);
 407 }
 408
 409 static struct cmdnames main_cmds, other_cmds;
 410
 411 static int is_git_command(const char *s)
 412 {
 413         if (is_builtin(s))
 414                 return 1;
 415
 416         load_command_list("git-", &main_cmds, &other_cmds);
 417         return is_in_cmdlist(&main_cmds, s) ||
 418                 is_in_cmdlist(&other_cmds, s);
 419 }
 420
 421 static const char *cmd_to_page(const char *git_cmd)
 422 {
 423         if (!git_cmd)
 424                 return "git";
 425         else if (starts_with(git_cmd, "git"))
 426                 return git_cmd;
 427         else if (is_git_command(git_cmd))
 428                 return xstrfmt("git-%s", git_cmd);
 429         else
 430                 return xstrfmt("git%s", git_cmd);
 431 }
 432
 433 static void setup_man_path(void)
 434 {
 435         struct strbuf new_path = STRBUF_INIT;
 436         const char *old_path = getenv("MANPATH");
 437         char *git_man_path = system_path(GIT_MAN_PATH);
 438
 439         /* We should always put ':' after our path. If there is no
 440          * old_path, the ':' at the end will let 'man' to try
 441          * system-wide paths after ours to find the manual page. If
 442          * there is old_path, we need ':' as delimiter. */
 443         strbuf_addstr(&new_path, git_man_path);
 444         strbuf_addch(&new_path, ':');
 445         if (old_path)
 446                 strbuf_addstr(&new_path, old_path);
 447
 448         free(git_man_path);
 449         setenv("MANPATH", new_path.buf, 1);
 450
 451         strbuf_release(&new_path);
 452 }
 453
 454 static void exec_viewer(const char *name, const char *page)
 455 {
 456         const char *info = get_man_viewer_info(name);
 457
 458         if (!strcasecmp(name, "man"))
 459                 exec_man_man(info, page);
 460         else if (!strcasecmp(name, "woman"))
 461                 exec_woman_emacs(info, page);
 462         else if (!strcasecmp(name, "konqueror"))
 463                 exec_man_konqueror(info, page);
 464         else if (info)
 465                 exec_man_cmd(info, page);
 466         else
 467                 warning(_("'%s': unknown man viewer."), name);
 468 }
 469
 470 static void show_man_page(const char *page)
 471 {
 472         struct man_viewer_list *viewer;
 473         const char *fallback = getenv("GIT_MAN_VIEWER");
 474
 475         setup_man_path();
 476         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 477         {
 478                 exec_viewer(viewer->name, page); /* will return when unable */
 479         }
 480         if (fallback)
 481                 exec_viewer(fallback, page);
 482         exec_viewer("man", page);
 483         die(_("no man viewer handled the request"));
 484 }
 485
 486 static void show_info_page(const char *page)
 487 {
 488         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 489         execlp("info", "info", "gitman", page, (char *)NULL);
 490         die(_("no info viewer handled the request"));
 491 }
 492
 493 static void get_html_page_path(struct strbuf *page_path, const char *page)
 494 {
 495         struct stat st;
 496         char *to_free = NULL;
 497
 498         if (!html_path)
 499                 html_path = to_free = system_path(GIT_HTML_PATH);
 500
 501         /*
 502          * Check that the page we're looking for exists.
 503          */
 504         if (!strstr(html_path, "://")) {
 505                 if (stat(mkpath("%s/%s.html", html_path, page), &st)
 506                     || !S_ISREG(st.st_mode))
 507                         die("'%s/%s.html': documentation file not found.",
 508                                 html_path, page);
 509         }
 510
 511         strbuf_init(page_path, 0);
 512         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 513         free(to_free);
 514 }
 515
 516 static void open_html(const char *path)
 517 {
 518         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 519 }
 520
 521 static void show_html_page(const char *page)
 522 {
 523         struct strbuf page_path; /* it leaks but we exec bellow */
 524
 525         get_html_page_path(&page_path, page);
 526
 527         open_html(page_path.buf);
 528 }
 529
 530 static const char *check_git_cmd(const char* cmd)
 531 {
 532         char *alias;
 533
 534         if (is_git_command(cmd))
 535                 return cmd;
 536
 537         alias = alias_lookup(cmd);
 538         if (alias) {
 539                 const char **argv;
 540                 int count;
 541
 542                 /*
 543                  * handle_builtin() in git.c rewrites "git cmd --help"
 544                  * to "git help --exclude-guides cmd", so we can use
 545                  * exclude_guides to distinguish "git cmd --help" from
 546                  * "git help cmd". In the latter case, or if cmd is an
 547                  * alias for a shell command, just print the alias
 548                  * definition.
 549                  */
 550                 if (!exclude_guides || alias[0] == '!') {
 551                         printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
 552                         free(alias);
 553                         exit(0);
 554                 }
 555                 /*
 556                  * Otherwise, we pretend that the command was "git
 557                  * word0 --help". We use split_cmdline() to get the
 558                  * first word of the alias, to ensure that we use the
 559                  * same rules as when the alias is actually
 560                  * used. split_cmdline() modifies alias in-place.
 561                  */
 562                 fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
 563                 count = split_cmdline(alias, &argv);
 564                 if (count < 0)
 565                         die(_("bad alias.%s string: %s"), cmd,
 566                             split_cmdline_strerror(count));
 567                 free(argv);
 568                 UNLEAK(alias);
 569                 return alias;
 570         }
 571
 572         if (exclude_guides)
 573                 return help_unknown_cmd(cmd);
 574
 575         return cmd;
 576 }
 577
 578 static void no_extra_argc(int argc)
 579 {
 580         if (argc)
 581                 usage_msg_opt(_("this option doesn't take any other arguments"),
 582                               builtin_help_usage, builtin_help_options);
 583 }
 584
 585 int cmd_help(int argc, const char **argv, const char *prefix)
 586 {
 587         int nongit;
 588         enum help_format parsed_help_format;
 589         const char *page;
 590
 591         argc = parse_options(argc, argv, prefix, builtin_help_options,
 592                         builtin_help_usage, 0);
 593         parsed_help_format = help_format;
 594
 595         switch (cmd_mode) {
 596         case HELP_ACTION_ALL:
 597                 if (verbose) {
 598                         setup_pager();
 599                         list_all_cmds_help();
 600                         return 0;
 601                 }
 602                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 603                 load_command_list("git-", &main_cmds, &other_cmds);
 604                 list_commands(&main_cmds, &other_cmds);
 605                 printf("%s\n", _(git_more_info_string));
 606                 break;
 607         case HELP_ACTION_GUIDES:
 608                 no_extra_argc(argc);
 609                 list_guides_help();
 610                 printf("%s\n", _(git_more_info_string));
 611                 return 0;
 612         case HELP_ACTION_CONFIG_FOR_COMPLETION:
 613                 no_extra_argc(argc);
 614                 list_config_help(SHOW_CONFIG_VARS);
 615                 return 0;
 616         case HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION:
 617                 no_extra_argc(argc);
 618                 list_config_help(SHOW_CONFIG_SECTIONS);
 619                 return 0;
 620         case HELP_ACTION_CONFIG:
 621                 no_extra_argc(argc);
 622                 setup_pager();
 623                 list_config_help(SHOW_CONFIG_HUMAN);
 624                 printf("\n%s\n", _("'git help config' for more information"));
 625                 return 0;
 626         }
 627
 628         if (!argv[0]) {
 629                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 630                 list_common_cmds_help();
 631                 printf("\n%s\n", _(git_more_info_string));
 632                 return 0;
 633         }
 634
 635         setup_git_directory_gently(&nongit);
 636         git_config(git_help_config, NULL);
 637
 638         if (parsed_help_format != HELP_FORMAT_NONE)
 639                 help_format = parsed_help_format;
 640         if (help_format == HELP_FORMAT_NONE)
 641                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 642
 643         argv[0] = check_git_cmd(argv[0]);
 644
 645         page = cmd_to_page(argv[0]);
 646         switch (help_format) {
 647         case HELP_FORMAT_NONE:
 648         case HELP_FORMAT_MAN:
 649                 show_man_page(page);
 650                 break;
 651         case HELP_FORMAT_INFO:
 652                 show_info_page(page);
 653                 break;
 654         case HELP_FORMAT_WEB:
 655                 show_html_page(page);
 656                 break;
 657         }
 658
 659         return 0;
 660 }